Next Wednesday is Dog Sniff day at the Supreme Court, when the Court will hear oral argument in Florida v. Jardines and Florida v. Harris. It’s Christmas in October for Fourth Amendment nerds, and I wanted to offer some thoughts on both cases. Before I begin, I should say that I’ve provided some modest assistance to the defense side in both cases. But everything I am saying here is just my personal opinion.

I. Florida v. Jardines

Florida v. Jardines raises the question of when the police can take a drug-sniffing dog up to the front steps and front door of a single-family home to sniff for the smell of drugs emanating from inside. Either they can do that whenever they want (the government’s view), or they can do so only with a warrant (the defendant’s view). The choice is pretty stark, and I suspect most people and most Justices will have an intuitive sense that either it’s perfectly fine to bring the dog to the front steps or it’s a pretty dangerous practice that clearly steps over the line. There’s lots of room in existing doctrine for either result, so in many ways the case boils down to which instinct prevails: Do you see this as a case of the police going wherever the public can go or as a case of the police using a very sensitive surveillance device to monitor the inside of the home?

Although I think either result is doctrinally plausible in Jardines, I tend to think the defense has the better argument. To my mind, the key is that the front steps of a private single-family home is space generally protected by the Fourth Amendment: In the argot of the doctrine, it is “curtilage,” not open fields. The issue then becomes the scope of implied consent to walk up to the front steps based on prevailing social norms. Cf. Georgia v. Randolph. I think there is implied consent for all the routine circumstances in which government actors might come to the front steps. The mailman drops off the mail, for example, and a a police officer might on occassion come to ask questions about crime in the neighborhood. But I see the pairing of a trained drug-sniffing dog and a police officer from a k-9 unit who has been trained to work with the dog as pretty obviously different. I would say that this is beyond the implied consent of homeowners, as it’s the rare homeowner who welcomes a drug-sniffing dog and trained handler to smell for drugs to get probable cause to break down the door to their home. That’s part of the reason why the police have had drug-sniffing dogs for a long time but have rarely used them at the home: It’s pretty different from the usual knock-and-talk, and most officers get that. At the same time, my rationale would be limited to homes surrounded by curtilage, such as single-family homes. I think it’s a different case with apartment buildings where there is no curtilage. In that case the apartment-dweller normally has no Fourth Amendment right to keep people away from the door.

II. Florida v. Harris

In Harris, the issue is how we know that a drug-sniffing dog is sufficiently trained that its alert creates probable cause that can then justify a search. A dog might be a reliable drug-detector or might not be, but it’s not like we can put the dog on the stand and have defense counsel cross-examine him about whether he really smelled the drugs. The state argues that judges should defer to canine professionals for the probable cause determination: If canine professionals announce that the dog has been trained, then the dog’s alert is always probable cause. The defense argues that we can’t rely on canine professionals and that we need to know the dog’s record of success in past searches to know whether the dog’s alert is reliable.

I think Harris is a hard case. The reliability of a drug-sniffing dog and the idea of a “trained” versus “untrained” dog is an abstraction for most of us. We don’t know much about what this “training” consists of, as there don’t appear to be any real standards for what training is. The state argues that a dog’s sense of smell is so fantastic that we don’t need to worry about this; any certification that isn’t a sham is enough. The defense offers a very different picture, as it presents some dogs as sufficiently trained that their alerts will be probable cause and others trained poorly so that their alerts won’t be probable cause. Based on the briefs, I find it hard to know which side is right on this.

So how should the Court decide the case? By rejecting absolutes, I think. First, I don’t think it makes sense to say that an alert by a “certified” dog automatically creates probable cause. We just don’t know enough about the “certification” process to know if that’s true (indeed, there is no one certification standard, so it’s hard to know what that even means). At the same time, I don’t think it makes sense to say that the state has to produce the records of past alerts to establish probable cause in each case. Probable cause always depends on the circumstances and a close look at all the facts. As we lawyers put it, it requires considering “the totality of the circumstances.” In some cases, the dog sniff alone should be enough to create probable cause. In other cases, it won’t be, and the state would be free to put on other evidence to try to meet its burden (including records of past alerts). I don’t think there’s a one-size-fits-all answer to the question. So I think the Court should emphasize the fact-specific nature of the question and the government’s burden of proof to justify the warrantless search, and then remand to the state supreme court.

I also wanted to flag one very interesting sub-issue in Harris. When a dog alerts but no drugs are found, was the dog “wrong” to alert? The state says that the dog may have alerted properly even if no drugs are recovered, as the dog has been trained to smell for certain chemicals which may be present even if no drugs are actually recovered. For example, the dog might be alerting to residual odors of the drug that don’t lead to recoverable amounts. The defense says that this alert is nonetheless a false alert, as there were no drugs to be found. The disagreement implicates an interesting issue: Does probable cause to believe contraband is inside a space mean probable cause to believe that enough contraband is there so that contraband can be recovered? Or does it mean probable cause to believe that even just a trace amount of contraband is there, even if it is not enough to be recovered? We don’t run into that problem with most kinds of evidence. Imagine the police apply for a warrant to search a home for a stolen diamond. Either the diamond is there or not: It’s an on-off switch. But drugs can appear in trace amounts, and a dog might alert to an amount that the police can’t actually recover. It’s an interesting issue to watch for in Wednesday’s arguments.